After continued criticism of large dam projects by International Rivers, a new study has found that dams in sub-Sahara are partly to blame for spread of malaria in the region. These criticisms revive the debate as to whether large dam projects are to be actively pursued in order to fill the huge power gap facing the continent, as well as providing water for drinking and irrigation.

While there are no doubts as to the importance of large dams - the largest single source of renewable energy in the continent, the claims put more doubt as to whether large dam projects should be actively pursued to fill the huge power gap facing the continent, as well as provide water for drinking and irrigation. They further shift the debate towards adequacy of dam project planning, adequacy of malaria prevention initiatives and the need to pursue other agile power generation alternatives such as wind and solar power given that they are becoming cheaper.

Benefits versus problems of large dams

Most of the large dams in sub-Saharan Africa are developed for hydropower purposes although many also act as sources of water for drinking and irrigation. For many sub-Saharan governments, dams are still an important strategy in increasing power generation capacity which remains low in the region. Many proponents of dams argue that their benefits, including bringing cheap and clean power to the masses and creating job opportunities and tax generation, outweigh their social and ecological damage. Do all the benefits actually hold in light of the criticisms?

Of greatest concern is probably the negative health and human effects, with their role in Malaria spread now quantified. "A total of 1.1 million malaria cases annually are associated with them (large dams): 919,000 cases due to the presence of 416 dams in areas of unstable transmission and 204,000 cases due to the presence of 307 dams in areas of stable transmission," so says the Malaria Journal in a study published earlier this month. Although there were previous claims of how large dams cause the spread of Malaria spread, the study is a huge achievement since it statistically quantifies these claims. The study by the Malaria Journal found that 15 million people who live within 5 kilometers of dam reservoirs are at the highest risk of contracting malaria. Of the over half a million global annual Malaria deaths, 90% occur in the sub-Sahara making it a hard-to-ignore factor wwhen developing any large water resource.

Other huge problems associated with large dams include displacement of people to create room for reservoirs, loss of ecological habitats as reservoirs deplete water downstream, and reduction of famland fertility as a result of related seasonal flooding.

It also appears that the cost benefit analysis of large hydrodams in sub-Sahara does not favor development of these resources, with the study confirming that they have an associated cost overrun of 56% - meaning a dam expected to cost $1 billion will likely end up costing $1.56 billion. This means most are largely uneconomical and that the burden is pushed to the final electricity consumer, thus denting the claim of their provision of cheap power. It appears most of these projects have been pursued amidst huge political optimism that does not take into consideration the potential problems, with good examples from Africa. Although, there is no doubt that careful planning may have helped avert environmental crisis in some dam cases, most are affected by continued lack of rain and thus fall short of the expected power generation capacities.

Decentralized, efficient water and power infrastructure

The fact that large dams are associated with many environmental shortfalls leaves experts thinking of whether there are better alternatives. There is no doubt that the 21st century is full of options for power sources with solar, wind, biomass and other alternatives becoming cheaper day by day. Agile energy alternatives such as solar and wind need be pursued actively to complement large hydrodams. These are associated with lesser environmental impacts than those reported from large dams and coal power alternatives.

Of course, utility-scale solar, wind and biomass alternatives come along with their challenges too - especially on cost aspects when compared to hydrodams, to the extent that hydropower ends up being cheaper in developing countries - therefore these countries would consider it hard to let go of more dam projects. That is bound to change in the future given the technological advances in renewable power alternatives - utility-scale solar and wind power alternatives that are cheaper than hydropower have been reported elsewhere but are yet to actualize in the sub-Sahara region. Home-based solar options compete favorably with regard to cost but development of utility-scale alternatives is important in order to satisfy large commercial applications. Thus, for now, there is no doubt that careful persuance of all options is needed in developing countries.